Holistic Approach to Control Sealice in Salmon Farming

Holistic Approach to Control Sealice in Salmon Farming

Author: Richard Cranfield, FAI Farms

Sealice have become endemic across much of the salmon farming industry. It causes severe health and welfare problems for the affected farmed salmon and associated wild stocks, environmental concerns are associated with chemical treatment programs and the economic cost to producers is estimated at $480 million. Our work in aquaculture revolves around helping the industry become more sustainable in terms of Economics, Environment and Ethics. This is also the framework we deploy when aiming to tackle serious the disease challenges that the industry faces. We have a multipronged approach encompassing: breeding and genetics, research and cleaner fish production and provision of better diagnostics and aquaculture health services.

FAI’s Ardtoe Marine Research Facility is pioneering the production of so-called ‘cleaner fish’ that can be used for the biological control of sea lice on salmon. The use of such fish species could negate the need to use various anti–parasitic chemicals in the fight against sealice.

Cleanerfish, such as wrasse and lumpfish, are currently being used on salmon farms in Norway, Canada and Scotland as a more environmentally friendly way of reducing sea lice, and interest in using them is growing. At our research facility the team is producing lumpfish and wrasse for commercial sale.

Our work in producing lumpfish sustainably has also reached a crucial milestone recently. Dr Jim Treasurer, Research Director of FAI Aquaculture in Ardtoe, reported that the technology for hatchery rearing lumpsuckers has progressed well, with excellent survival and rapid growth from egg to stocking. The major breakthrough came in May 2015, however, when Ardtoe researchers managed to get stocks of hatchery-reared lumpsuckers to produce their first batch of viable eggs successfully. Dr Treasurer noted that a key bottleneck in lumpfish production had been the need to collect eggs from wild adults captured when they enter inshore waters in spring to spawn.

Commenting on the closing of the lifecycle of lumpsuckers, the ManagingDirector of FAI Ardtoe, Dr Tim Atack, said: “Not only does this breakthrough make the large scale production of lumpsuckers more viable and sustainable, it has also opened up opportunities for us to develop strains of lumpsuckers that are more resistant to disease, and better at cleaning lice.”

Our colleagues at our sister company SalmoBreed has been selecting fish for sea lice resistance since 2007. “Our test shows that it is the same animal that has high/low lice in consecutive tests and that there is high variance from the best to the worst performing animals,” Mr Seim explained. “In the first test we performed the average of the worst performing family was 89 sea lice per individual whereas the best
family had only seven sea lice per individual.” Based on this knowledge, we habe been able to choose the best families for further reproduction and the good results have been verified in their offspring. “We are also on the doorstep of validating some new genetic markers that will further help fuel the selection of the best performing salmon for sea lice robustness,” Mr Seim stated.